Common Map Turtle

Graptemys geographica

Excerpted from: Animal Diversity

  Description

Common Map Turtles get their name from the markings on the carapace. The light markings resemble waterways on a map or chart. The lines on the carapace are a shade of yellow or orange and are surrounded by dark borders. The rest of the carapace is olive or grayish brown. The markings on the older turtles may be barely visible because of darker pigment.

The carapace is broad with moderately low keel. The hind of the carapace is slightly scalloped shaped due to the scutes. The plastron of an adult map turtle tends to be plain yellowish color. The head, neck and limbs are dark olive, brown or black with thin yellow, green or orangish stripes. There is also an oval spot located behind the eye of most specimens.

There is sexual dimorphism in size and shape. The females are much larger than the males. The males also have a more oval carapace with more distinct keel, narrower head, longer front claws, and a longer thicker tail. The males vent also opens beyond the edge of the carapace whereas the female's open up the carapace. The young Map Turtles have a pronounced dorsal keel and patterns on the plastron consist of dark lines bordering the scutes. A hatchling has rounded gray or grayish-brown carapace about 1 inch long. The pattern is light circular markings. The stripes located on the head and limbs are just like the adults.

  Lifespan

In the wild Common Map Turtles are estimated to live up to 6 years.

  Behavior

The Common Map Turtle is dormant from November through early April. Most of that time is spent under the water, wedged beneath submerged logs, in the bottom mud of a lake or in a burrow. They have been known to change locations in the middle of the winter. They are avid baskers and they bask in groups. They are diurnal, active both in the day and at night (Harding 1997). They are also a very wary animal, at the slightest hint of danger they slip into the water and hide.

During courtship the male initiates by tapping his long claws on the front of the female but few details are known.

  Diet

Common Map Turtles are omnivores. The feeding always takes place in the water. The adult females, due to their large heads and strong jaws eat larger prey than the males. The females consume snails, clams, and crayfish. The males eat aquatic insects, snails, and smaller crustaceans. Both are also known to eat dead fish and some plant material.

Further Reading:

 Beavers — Nature's Hydrologist, Part 2
 Garter Snakes — The Gardener's Friend
 Wisconsin Native Salamanders
 Goundhog or Woochuck: All The Facts
 Voles, Both The Good and The Bad